Differential inducibility of angiotensin II AT(2) receptor between SHR and WKY vascular smooth muscle cells

Although the fetal aorta expresses a substantial amount of angiotensin II type 2 receptors, the expression level of angiotensin II type 2 receptors in the adult aorta and cultured vascular smooth muscle cells is very low or even absent. Prolonged serum depletion (6 to 8 days) with a supplement of insulin, transferrin and sodium selenite induced angiotensin II type 2 receptors and mRNA in cultured vascular smooth muscle cells from Wistar Kyoto rats. Insulin was found to be essential for the induction of the receptor. However, these receptors could not be induced in cultured vascular smooth muscle cells from spontaneously hypertensive rats. These results suggest that: (1) insulin plays an important role for the expression of the angiotensin II type 2 receptor gene; and (2) the type 2 receptor gene expression is differentially regulated between cultured vascular smooth muscle cells of Wistar Kyoto rats and spontaneously hypertensive rats.